Control method for combustion system, combustion system, and diesel engine

A method for controlling a combustion system, wherein the combustion system comprises a piston, an injector, and a cylinder, the piston is configured to reciprocate up and down in the cylinder, the injector is configured to execute at least a first main fuel injection and a second main fuel injection in sequence during each movement cycle of the piston, and the injector is configured to continuously inject fuel during a process from the first main fuel injection to the second main fuel injection;

• an injection pressure when a velocity of the fuel injected by the injector is highest during the first main fuel injection executed by the injector is a first injection pressure, and an injection pressure when a velocity of the fuel injected by the injector is highest during the second main fuel injection executed by the injector is a second injection pressure;
• the method for controlling a combustion system comprising:
• determining a duration of the first main fuel injection and the first injection pressure to allow a cylinder pressure to reach a cylinder pressure upper threshold at least at partial moment during the first main fuel injection;
• and
• iteratively adjusting at least one of a duration of the second main fuel injection and the second injection pressure, to allow a change rate of curve slopes of a cylinder pressure change curve during a period when the cylinder pressure drops from the cylinder pressure upper threshold to a set cylinder pressure to be within a set range of slope change rates at any time point, and to allow an angle that a crankshaft has rotated during the period when the cylinder pressure drops from the cylinder pressure upper threshold to the set cylinder pressure to be not less than a first preset rotation angle in the second main fuel injection.